This invention relates to storage tanks and fluid injection systems, specifically to injection metering devices.
A variety of means have been used to inject fluids into fluid streams. These include metering pumps, water powered pumps, siphon devices, flow through devices and gravity feed drainage equipment.
There are a number of problems encountered with each type of equipment available in delivering an accurately proportioned injection amount. Metering pumps are either set to inject a predetermined amount into a fluid stream without a means of adjusting to changes in flow volume in the fluid stream, or they are controlled electronically by flow sensors located in the fluid stream. The components of this type of system are mechanical and electronic so they are subject to wear and mechanical failure. Water powered pumps adjust automatically to changes in flow in the fluid stream but are a mechanical device with a number of seal points. The seals require frequent maintenance for the unit to operate properly. This design is limited in the amount of fluid flow it can operate with and as flows increase, the cost of the device increases.
Siphon devices rely on a high restriction in the fluid stream to create venturi suction strong enough to pull the injection solution from the storage container. They require high pressure to operate and the high restriction in the fluid stream greatly reduces the fluid stream volume. Fluctuations in pressure can cause the device to not inject continuously creating uneven distribution. They are also unable to dependably inject solutions such as water-soluble fertilizers without plugging. Venturi systems generally have relatively small flow orifices and the fertilizer solution has a tendency to settle, creating sedimentation that plugs these orifices. Flow through devices typically channel the flow of the fluid stream through a container that holds a soluble product that slowly breaks down, releasing the product into the stream. This method doesn""t control the amount being distributed and can give unreliable distribution. It is common for the soluble products to melt as they sit in the water while the system is not operating and release a large amount when the system is restarted.
Several types of fluid injectors have been developed to proportion liquid or soluble fertilizers or chemicals into fluid piping systems. My U.S. Pat. No. 5,484,106, Automatic Pressurized Adjustable Solution Dispenser accomplishes this task but relies on a check valve to prevent back flow of contaminants into the fluid stream. With this design, the outlet flow port connection needs to extend to the bottom of the storage tank to establish a consistent injection rate of fertilizers, which have a higher specific gravity than the incoming water. When the outlet port connection is extended to the bottom of the storage tank, the system develops an air pocket in the top of the storage tank that can only be eliminated by manually filling the tank with fluid or some other means of manually venting the system. If the air is not removed from the system, a potentially hazardous condition exists in that air compresses under pressure, which creates a higher stress on the storage tank than fluids under pressure and can cause the storage tank to rupture at much lower operating pressures. The presence of air also reduces the amount of fluid in the storage tank. This limits the fluid available to mix with soluble products to make them an injectable solution, causing the system to not inject accurately or possibly not inject at all due to plugged flow ports. Since there is no way for air to escape the storage tank, soluble products must be premixed and the tank filled with water before using the system. Many soluble products begin settling to the bottom of the tank immediately after being mixed. Continual agitation is required to keep them in an injectable state. This requires extending the inlet port near the bottom of the storage tank to direct flow through the soluble product. Also, this design does not provide a means of injecting more than one solution from the same tank at independent ratios.
The U.S. Pat. No. 4,846,214, Fluid Additive Injector by Thomas F. Strong has an automatic mechanical air relief valve that vents air from the storage tank to the atmosphere. While it does evacuate the air from the tank automatically, it is mechanical in nature so it is subject to wear and eventual failure. It does not provide back flow protection, establish proportioning rates or allow air to be vented through the piping system. It also does not provide a means of injecting more than one solution from the storage tank at independent ratios.
The U.S. Pat. No. 3,809,291, Liquid Proportioning System by Chester A. Purdy is a gravity feed system that uses an internal mixing chamber to combine two liquids to be dispensed into a fluid stream. It requires an electrical controller, a pressure switch and a float valve to control fluid flow into the tank.
The U.S. Pat. No. 5,544,810, Precision-Ratioed Fluid-Mixing Device And System by Horvath, Abrams and Helf utilizes a high pressure flow line to create a venturi to draw multiple fluids from multiple unpressurized containers and accurately mix them into one solution. The system has an air vent to the atmosphere to prevent siphoning of fluid from the storage containers when the system is not operating. This design requires a high-pressure flow line to create enough vacuum to draw fluids from the containers. This creates a high restriction in the flow line, significantly reducing flow volume and pressure. It also requires multiple containers to store the various solutions, which requires piping connections between all the containers used. This design cannot operate at low pressures or automatically mix dry products and keep them an injectable solution.
The U.S. Pat. No. 6,039,065, Fluid Proportioning Valve And Method by John P. Gagliardo is mixing valve that combines liquids at controllable proportions. It does not provide for the injection of liquids into a flow line, only the mixing of incoming flows.
My invention solves a number of problems that have been present in prior art. It eliminates the need for a mechanical check valve and air relief valves, which are subject to wear, leakage and failure. It operates at very low pressures without the need for restriction in the flow line. It operates totally on pressure from the flow line and injects very accurately. It can handle dry products as well as very heavy products without plugging or manual mixing. It can inject multiple solutions at independent injection rates from one storage tank.
Accordingly, the objects and advantages of my invention are:
(a) Provides the ability to accurately inject one or more liquid solutions into a fluid stream at independent injection rates.
(b) Soluble products can be put in the storage tank dry and the system will exhaust all air from the storage tank while mixing the products automatically, eliminating manual mixing and plugging.
(c) Provides back flow and siphoning protection with the need for mechanical check valves and air relief valves, which makes the system more dependable, less expensive to manufacture, have a longer service life and require less maintenance.
(d) Flow control allows a wide range of injection rates, which gives the user the ability to apply the products in minutes or over weeks or months.
(e) Highly concentrated product can be used, which reduces storage requirements.
(f) There are no moving parts to wear out or break. All operations are controlled by system flow.
(g) Little exposure to hazardous chemicals. The chemicals can be applied in very low amounts automatically, which eliminates any exposure during the application process as well as better absorption rates, reducing negative environmental impact.
(h) Mixing incoming fluid with the outgoing solution makes the injection rate slower so flow ports can be made larger which allows more fluid through the system, which prevents plugging, improves mixing and improves injection accuracy.
(i) Inlet connections can be extended to the bottom of the tank to provide agitation of soluble or heavy products, which keeps them in a more injectable state and eliminates the need for manual mixing when the system is initially filled. It also allows a higher concentration of product to be put in the storage tank.
(j) Outlet connections can be extended to the bottom of the tank to provide consistent, accurate metering of the injected solution.
(k) Provides a consistent injection stream so the injected solution is more evenly mixed in the flow line.
(l) Operates a very low flow rates and pressures with no restriction on the flow line pressure or volume, giving it a broad range of use in many applications.
(m) Responds to the smallest changes in pressure or velocity in the flow line, making it very accurate in all applications.
(n) Convenient emptying and filling of single or multiple solutions. Still further objects and advantages will become apparent in the ensuing drawings and descriptions.
In accordance with the present invention a fluid injector with vent/proportioner ports comprises a fluid injector that utilizes fluid from a flow line to accurately inject fluids into the flow line. The system mixes incoming fluid with outgoing injection solution to provide a wide range of flow adjustment. It uses flow orifices to provide air release from the storage tank as well as provide back flow protection. It utilizes multiple bladders to inject multiple solutions from one storage tank.